In recent years, research on organic electroluminescent (hereinafter, may also be referred to as “organic EL”) displays, organic EL lightings, and various organic electronic devices such as organic semiconductors and organic solar cells has been actively conducted, and these devices are expected to serve as the next-generation displays that will replace liquid crystal displays (LCD's), or as the next-generation lightings that will replace light emitting diode (LED) lightings. Furthermore, since organic EL elements are such that all of the constituent elements thereof can be formed from solid materials, there is a possibility that organic EL elements may be used as flexible displays or lightings. An organic EL element has a basic configuration in which an anode layer, a light emitting layer, and a cathode layer are sequentially formed on a substrate made of glass or the like. As a voltage is applied between the anode layer and the cathode layer, the organic EL element undergoes self-luminescence, and light can be extracted from either side of the anode layer and the cathode layer. Therefore, a top emission mode and a bottom emission mode are available as the light emission mode of organic EL devices.
However, regarding the organic EL elements described above, if moisture, impurities and the like exist in the periphery of an element, non-light emitting areas called dark spots are generated and grow. When the dark spots grow to have a diameter of several ten micrometers (μm), the non-light emitting areas can be identified by visual inspection, and this leads to deterioration of visibility.
Thus, in order to shield an organic EL element from moisture, impurities and the like, the organic EL element is provided with a transparent sealing substrate made of glass or the like (also available is a sealing can), and an organic EL device in which a viscous material containing a dehydrating agent is filled in a space produced between the organic EL element and the sealing substrate has been disclosed (see, for example, Patent Document 1). However, it is necessary to use a dam material so as to prevent the viscous material from overflowing at the time of charging, and it was not possible to obtain a flexible organic EL device.
In order to obtain a flexible organic EL device, a method of sealing an organic EL device with a transparent sealing material formed from a thermoplastic resin has been disclosed (see, for example, Patent Document 2). However, the effect of shielding against moisture has not been sufficient.